Eglish was territory of the Ó Maolmhuaidh (O'Molloy) of the Southern Uí Néill, prince of Firceall (Fir Cell, "men of the churches").[2] During its existence Firceall was the location of a number of ancient abbeys and castles. The church at Lynally (near Tullamore) formed the parish church until the foundation of parish churches at Rahan, Killoughey, Ballyboy, Drumcullen and Eglish. A number of known ancient abbeys were located at Drumcullen, Killyon, Kilcormac and Rahan.